cleanup: pass string as const reference from c/b/extension/api

chrome/browser/extensions/api/file_system/file_system_api_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file_path.h"
 #include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
 
 using extensions::FileSystemChooseEntryFunction;
 using extensions::api::file_system::AcceptOption;
 
 namespace {
 
 void CheckExtensions(const std::vector<base::FilePath::StringType>& expected,
     std::vector<base::FilePath::StringType>& actual) {
   EXPECT_EQ(expected.size(), actual.size());
   if (expected.size() != actual.size())
     return;
 
   for (size_t i = 0; i < expected.size(); ++i) {
     EXPECT_EQ(expected[i], actual[i]);
   }
 }
 
-AcceptOption* BuildAcceptOption(std::string description,
-    std::string mime_types,
-    std::string extensions) {
+AcceptOption* BuildAcceptOption(const std::string& description,
+                                std::string mime_types,

[Devlin, 2014/05/02 15:34:15]

why not also make the other two params const &?

[limasdf, 2014/05/02 16:26:46]

Done. I dont know why-_- I didn't

+                                std::string extensions) {
   AcceptOption* option = new AcceptOption();
 
   if (!description.empty())
     option->description.reset(new std::string(description));
 
   if (!mime_types.empty()) {
     option->mime_types.reset(new std::vector<std::string>());
     base::SplitString(mime_types, ',', option->mime_types.get());
   }
 
@@ skipping 51 matching lines @@
       BuildAcceptOption(std::string(), std::string(), "unrelated")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       ToStringType(".jso"), &options, &acceptsAllTypes);
   EXPECT_TRUE(file_type_info.include_all_files);
 
   // Test multiple list entries, all containing their own types.
   file_type_info = ui::SelectFileDialog::FileTypeInfo();
   options.clear();
   options.push_back(linked_ptr<AcceptOption>(
       BuildAcceptOption(std::string(), std::string(), "jso,js")));

[Devlin, 2014/05/02 15:34:15]

Yet another "while you're here" request. :)

Can you please replace all instances of "std::string()" in this file with
"base::EmptyString()"?  It saves us on the many constructions of new strings
that we don't need.  Admittedly, it's a unittest, so speed isn't as vital, but
it's a good practice.

[limasdf, 2014/05/02 16:26:46]

Done.

   options.push_back(linked_ptr<AcceptOption>(
       BuildAcceptOption(std::string(), std::string(), "cpp,cc")));
   acceptsAllTypes = false;
   FileSystemChooseEntryFunction::BuildFileTypeInfo(&file_type_info,
       base::FilePath::StringType(), &options, &acceptsAllTypes);
   ASSERT_EQ(file_type_info.extensions.size(), options.size());
 
   expectedTypes.clear();
   expectedTypes.push_back(ToStringType("js"));
   expectedTypes.push_back(ToStringType("jso"));
@@ skipping 64 matching lines @@
   // TODO(thorogood): Fix this test on Windows.
   // Filter out absolute paths with no basename.
   opt_name = std::string("/");
   FileSystemChooseEntryFunction::BuildSuggestion(&opt_name, &suggested_name,
       &suggested_extension);
   EXPECT_FALSE(suggested_name.IsAbsolute());
   EXPECT_TRUE(suggested_name.MaybeAsASCII().empty());
   EXPECT_TRUE(suggested_extension.empty());
 #endif
 }